This invention relates generally to fluid control systems. More particularly, this invention relates to a modular mounting system for chemical fluid control components of a chemical fluid control system.
Fluid control components are used to control the delivery of a fluid (i.e., a gas or liquid) in industrial processes. These components are arranged so that fluid is carried through each of the components. Chemical delivery systems are used in numerous industries to control the flow of fluids, including gas reactants and other chemicals (e.g., liquids). In general, process control of fluid production requires the selection, conditioning, and metering of specific fluids, which are then routed to analytical equipment. The fluid control system is known as a sampling system, reflecting its main function of drawing a small portion of the main fluid being produced and returning it the main stream after analysis is complete.
In the production of petrochemicals, a fluid is sampled on demand and analyzed to identify the presence and quantity of its constituents. This sampling analysis is used as process control in a feedback manner to keep desired results constants.
In other industries, it is required that a mixture of precisely metered amounts of chemicals be delivered to a reactor vessel. A variety of fluid control components are configured to control the delivery of various fluids during processing. In these industries the fluid control system is known as a gas panel containing a plurality of gas sticks, or components linked together to process each gas species or constituent.
Filtering, pressure regulation, flow metering, valving, and other flow control functions are needed to design a fluid flow control systems. It is common practice to link discrete components performing each of these functions using piping and fluid connectors. Most of these systems require custom design, welding, and machining. FIG. 1 illustrates an existing fluid control assembly 20. The fluid control assembly 20 includes a set of fluid control components joined by multiple welds and fittings. One fluid-control component depicted in FIG. 1 is a shut-off valve 22. A pipe section 26 links the shut-off valve 22 to a sleeve or fitting 28 associated with a pressure regulator 24. The pressure regulator 24 has a fitting 30 on its opposite side for connection with a pipe section 32. Pipe section 32 is connected to a fitting 36 associated with a pressure transducer 34. The opposite side of the pressure transducer 34 also has a fitting 38 for connection with another pipe section. Check valve 40 is connected to fitting 38, followed by component 42, mass flow controller 44, and finally valve 46. The fluid control assembly 20 is attached to a substrate 50.
Those skilled in the art recognize a number of problems associated with prior art gas sticks of the type illustrated in FIG. 1. First, the multiple fittings and pipe sections need to be welded or otherwise secured to one another. The assembly of these components can be relatively labor intensive. Similarly, the disassembly of these components for repair or replacement can be labor-intensive and costly.
Another problem associated with fluid control assembly is that the numerous fittings and pipe sections produce a relatively long and heavy device. The attachment of the fluid control assembly to a substrate also produces problems since the entire fluid assembly must be removed from the substrate in order to repair the gas stick.
In addition, for each part of the substrate assembly, a distinctly different substrate component is often required for each type of function required for the process. This forces the user to purchase many different types of fluid control components in preparation for multiple options at the time of assembly. This increases the amount of in-house stock required for daily operation, resulting in higher operation costs and an increase in the complexity of the assembled system.
Another problem experienced with existing systems is the inability to purge individual components and fluid passages without purging the surrounding components and fluid passages. Purging is necessary when dealing with reactive chemicals that need to be removed from the system before introducing an additional fluid.
Additionally, when face seal or compression-type fittings are utilized to connect the various fluid control components, undesirable torque can be transmitted throughout the gas stick. The operator can “chase” a leak in the gas stick by tightening one fitting, only to find that the resulting torque has loosened another fitting, causing it to leak. This process is lengthy and often ineffective.
What is needed is a fluid control system that is relatively easy to configure and assemble, lightweight, minimizes the required number of parts, does not substantially transmit torque throughout the system, allows for purging between sticks, allows purging of specific component assemblies while avoiding surrounding components, and requires no welding for assembly.